Antenna structure and electronic device having same

Abstract

A dual-band Wi-Fi antenna structure includes a metallic middle frame of a casing of a handheld electronic device, a grounding plane received in the middle frame, an antenna body connected to the grounding plane, and an adjusting element. The grounding plane defines a rectangular recess in a corner thereof. The antenna body has a radiation patch having a part located over the recess. The adjusting element is located in the recess. An effective length of the recess is adjustable by adjusting a parameter of the adjusting element, which is a coefficient of self-inductance when the adjusting element is an adjustable inductor. By adjusting the effective length of the recess, a resonant frequency of the antenna structure at a low frequency band is adjustable, while a resonant frequency thereof at a high frequency band is not altered.

What is claimed is: 
     
       1. An electronic device with a dual-band antenna structure comprising:
 a metallic middle frame, the metallic middle frame including a first side wall and a second side wall connected to, and substantially perpendicular to, the first side wall; 
 a grounding plane configured to be received into the middle frame, the grounding plane having:
 a first side edge, having a first portion and a second portion; 
 a second side edge substantially perpendicular to both the first portion and second portion of the first side edge; and 
 a first face substantially perpendicular to the first side edge and to the second side edge; 
 
 wherein, when the grounding plane is received into the middle frame:
 the first portion and second portion of the first side edge are substantially parallel to the first side wall and the second portion of the first side edge is substantially adjacent the first side wall; and 
 the second edge of the grounding plane is substantially parallel to the second side wall and positioned substantially near the second side wall; and 
 wherein, the first portion of the first side edge, the first side wall and the second side wall cooperate to define a recess in the grounding plane and creating a recess space extending from the grounding plane with sides substantially perpendicular to the first face of the grounding plane; and 
 
 an antenna body electrically coupled to the grounding plane and having a radiation patch, the radiation patch positioned in a first plane substantially parallel to and spaced from the grounding plane, and the radiation patch suspended above the first face with at least a portion of the radiation patch extending into the recess space; 
 wherein the antenna body comprises a feed section connecting with the grounding plane, a grounding section connecting with the grounding plane, a first connection section connecting with the feed section, a second connection section connecting with the grounding section; 
 wherein the radiation patch comprises a first radiation section, a second radiation section and a third radiation section successively connecting with each other; 
 wherein the first radiation section, the second radiation section, the third radiation section, the first connection section, and the second connection section are coplanar; 
 wherein the first connecting section is spaced from the first radiation section and the third radiation section, and positioned between the first radiation section and the third radiation section; an end of the first connecting section is perpendicularly connected to the second radiation section, and another end of the first connecting section is spaced from the second connecting section. 
 
     
     
       2. The dual-band antenna structure of  claim 1 , further comprising an adjusting element received in the recess and electrically coupling with the metallic middle frame and the grounding plane, a resonant frequency of the dual-band antenna structure being adjusted by adjusting a parameter of the adjusting element. 
     
     
       3. The dual-band antenna structure of  claim 2 , wherein the adjusting element is an adjustable inductor and the parameter is a coefficient of self-inductance of the adjustable inductor. 
     
     
       4. The dual-band antenna structure of  claim 1 , wherein the antenna body is a planar inverted-F antenna. 
     
     
       5. The dual-band antenna structure of  claim 4 , wherein the radiation patch connecting with the first and second connecting sections, the radiation patch having a substantially U-shaped profile, the feed and the grounding sections are positioned in a second plane substantially perpendicular to the grounding plane. 
     
     
       6. The dual-band antenna structure of  claim 5 , wherein the grounding plane is substantially rectangular and the recess is rectangular and defined in neighboring first and second sides of the grounding plane, the first and third radiation sections being parallel to the first side of the grounding plane, the second radiation section being parallel to the second side of the grounding plane and interconnecting ends of the first and third radiation sections away from the second side of the grounding plane. 
     
     
       7. The dual-band antenna structure of  claim 6 , wherein the first radiation section is suspended above the recess and extends along a lengthwise direction of the recess. 
     
     
       8. The dual-band antenna structure of  claim 7 , wherein the dual-band antenna structure has a first resonant frequency at a low frequency band of 2.4 GHz and a second resonant frequency at a high frequency band of 5.15-5.85 GHz. 
     
     
       9. The dual-band antenna structure of  claim 8 , wherein the dual-band antenna structure is configured for Wi-Fi communication. 
     
     
       10. The dual-band antenna structure of  claim 7 , further comprising an adjustable inductor located in the recess and electrically coupled to the metallic middle frame and the grounding plane, a distance between the second side of the grounding plane and the adjustable inductor is 15 mm, a length of the recess is 30 mm and a coefficient of self-inductance of the adjustable inductor is 2.6 nH. 
     
     
       11. An handheld electronic device, comprising:
 a casing having a substantially rectangular metallic middle frame; 
 a substantially rectangular grounding plane received in the metallic middle frame, defining a recess in one of two top corners thereof; and 
 a planar inverted-F antenna for dual-band Wi-Fi communication having a feed section and a grounding section substantially perpendicularly connected to the grounding plane, and a substantially U-shaped radiation patch connected to the feed and grounding sections; 
 wherein the radiation patch is positioned in a first plane substantially parallel to and spaced from the grounding plane, and the radiation patch is suspended above the grounding plane and has at least a section located over the recess, the feed and the grounding sections are positioned in a second plane substantially perpendicular to the grounding plane; 
 wherein the antenna body comprises a feed section connecting with the grounding plane, a grounding section connecting with the grounding plane, a first connection section connecting with the feed section, a second connection section connecting with the grounding section; 
 wherein the radiation patch comprises a first radiation section, a second radiation section and a third radiation section successively connecting with each other; 
 wherein the first radiation section, the second radiation section, the third radiation section, the first connection section, and the second connection section are coplanar; 
 wherein the first connecting section is spaced from the first radiation section and the third radiation section, and positioned between the first radiation section and the third radiation section; an end of the first connecting section is perpendicularly connected to the second radiation section, and another end of the first connecting section is spaced from the second connecting section. 
 
     
     
       12. The handheld electronic device of  claim 11 , further comprising an adjusting element located in the recess and electrically coupling with the grounding plane and the metallic middle frame, a resonant frequency of the planar inverted-F antenna at a low frequency band being adjustable by adjusting a parameter of the adjusting element. 
     
     
       13. The handheld electronic device of  claim 12 , wherein the adjusting element is an adjustable inductor and the parameter is a coefficient of self-inductance of the adjustable inductor. 
     
     
       14. The handheld electronic device of  claim 13 , wherein the radiation patch has a first radiation section, a second radiation section and a third radiation section successively connected together to form a U-shaped configuration, the first radiation section being located over the recess and extending along a lengthwise direction thereof, the second radiation section interconnecting ends of the first and third radiation sections away from a top side of the of the grounding plane. 
     
     
       15. The handheld electronic device of  claim 14 , wherein the planar inverted-F antenna has a first connection section connecting the feed section with the second radiation section and a second connection section connecting the grounding section with the first radiation section, the first and second connection sections are coplanar with the radiation patch. 
     
     
       16. The handheld electronic device of  claim 15 , wherein the first connection section is straight and the second connection section is L-shaped. 
     
     
       17. The handheld electronic device of  claim 13 , wherein the recess has a length of 30 mm, a distance between the adjustable inductor and the top side of the grounding plane is 15 mm, and the coefficient of self-inductance of the adjustable inductor is 2.6 nH. 
     
     
       18. The handheld electronic device of  claim 17 , wherein the inverted planar-F antenna has a first resonant frequency at a low frequency band of 2.4 GHz, and a second resonant frequency at a high frequency band of 5.15-5.85 GHz. 
     
     
       19. The handheld electronic device of  claim 17 , wherein the metallic middle frame has a slit located near a top end of the recess and communicating therewith. 
     
     
       20. The handheld electronic device of  claim 11 , wherein the metallic middle frame has a slit located near a top end of the recess and communicating therewith. 
     
     
       21. A dual-band antenna structure for an electronic device having a casing having a metallic middle frame, comprising:
 a grounding plane configured to be received in the casing and surrounded by the metallic middle frame, the grounding plane defining a recess in a periphery thereof; and 
 an antenna body electrically coupled to the grounding plane and having a radiation patch; 
 wherein the radiation patch is in a first plane substantially parallel to and spaced from grounding plane, and the radiation patch is suspended above the grounding plane, the radiation patch has at least a part suspended above the recess; 
 wherein the antenna body comprises a feed section connecting with the grounding plane, a grounding section connecting with the grounding plane, a first connection section connecting with the feed section, a second connection section connecting with the grounding section; 
 wherein the radiation patch comprises a first radiation section, a second radiation section and a third radiation section successively connecting with each other; 
 wherein the first radiation section, the second radiation section, the third radiation section, the first connection section, and the second connection section are coplanar; 
 wherein the first connecting section is spaced from the first radiation section and the third radiation section, and positioned between the first radiation section and the third radiation section; an end of the first connecting section is perpendicularly connected to the second radiation section, and another end of the first connecting section is spaced from the second connecting section. 
 
     
     
       22. The dual-band antenna structure of  claim 21 , wherein the grounding plane is substantially rectangular in shape, and the recess is defined in a corner of the grounding plane. 
     
     
       23. The dual-band antenna structure of  claim 22 , further comprising an adjusting element received in the recess and configured to electrically couple with the metallic middle frame and the grounding plane, a resonant frequency of the dual-band antenna structure being adjusted by adjusting a parameter of the adjusting element. 
     
     
       24. The dual-band antenna structure of  claim 23 , wherein the dual-band antenna structure is used for dual-band Wi-Fi wireless communication.